Aviation Accident Summaries

Aviation Accident Summary LAX96LA048

IMPERIAL, CA, USA

Aircraft #1

N23102

Cessna 150H

Analysis

The airport elevation is 56 feet below sea level. In the pilot's navigation logs under the destination airport field elevation column, '-56' was entered with '(950alt)' written next to it. The traffic pattern altitude is listed as '944 msl (1,000 agl)' in the airport facility directory. The FBO line person who communicated with the pilot observed the first landing approach and reported that it appeared to be a little high. The aircraft then initiated a go-around and made right traffic for runway 32. Ground witnesses reported that during the aircraft's traffic pattern following the go-around, the aircraft flew an extremely low pattern estimated at 100 feet agl. The pilot then contacted the FBO line person on the radio a second time. The witness stated that the pilot seemed confused about the traffic pattern altitude and airport elevation. She reportedly ask what the field elevation was, and the witness responded with 60 feet below sea level. The witness stated that the pilot responded, 'I thought it was about 900 feet.' The pilot then terminated the second approach with another go-around. According to the witnesses, the third traffic pattern was flown about the same agl altitude as the second one. Shortly after the pilot reported turning base, the power went off at the airport. A ground witness near the accident site saw the aircraft turn at a very low altitude and collide with a 40-foot-tall power pole about 1/2 mile southeast of the airport. Detailed examination of the aircraft revealed no discrepancies in any system. Review of the sun's location revealed that as the pilot turned from downwind to base, she would have been looking almost directly into the sun.

Factual Information

On November 18, 1995, about 1507 hours Pacific standard time, a Cessna 150H, N23102, operated by Plus One Flyers, collided with a power pole and crashed on approach to the Imperial County (uncontrolled) Airport, Imperial, California. Visual meteorological conditions prevailed at the time of the solo instructional flight, and a VFR flight plan was filed. The airplane was destroyed, and the student pilot was fatally injured. The solo cross-country flight originated from Montgomery Field, San Diego, California, at 1135 and made a stop at Palm Springs. The pilot departed Palm Springs at 1400 with the intention of performing a full stop landing at Imperial, and then returning to San Diego. The Imperial County Airport's elevation is 56 feet below sea level. The pilot's navigation logs for the route segment from Palm Springs to Imperial were recovered from the aircraft and examined. Under the destination airport field elevation column "-56" was entered. Adjacent to that number was written "(950alt)." In the NOAA Airport Facility Directory, the traffic pattern altitude is listed as "944 msl (1,000 agl)." The airport does not have an Air Traffic Control Tower, and air-to-ground advisories on airport and traffic conditions are conducted over the Common Traffic Advisory Frequency (CTAF). Radio communications on the CTAF are not recorded. The CTAF at the airport is monitored by a Fixed Base Operator (FBO), Imperial Flying Service. The line person on duty the day of the accident was interviewed by FAA inspectors from the San Diego, California, Flight Standards District Office. The witness reported that the pilot called on the CTAF for airport advisories while inbound to the field and was told that runway 32 was active and the winds were calm. The witness observed the aircraft's first landing approach and reported that it appeared to be "a little high." The aircraft then initiated a go-around and made right traffic for runway 32. Ground witnesses on and around the airport reported that during the aircraft's traffic pattern following the go-around, the aircraft was extremely low with some individuals reporting a value of 100 feet agl. The witnesses, including one pilot-rated witness, said the engine power level was steady, but a lower than full power setting. The pilot then contacted the FBO line person on the radio. The witness stated that the pilot seemed confused about the traffic pattern altitude and airport elevation. She reportedly ask what the field elevation was, and the witness responded with "60 feet below sea level." The witness stated that the pilot responded, "I thought it was about 900 feet." The pilot then terminated the second approach with another go-around. According to the witnesses, the third traffic pattern was flown about the same agl altitude as the second one. Shortly after the pilot reported turning base, the power went off at the airport. A ground witness near the accident site saw the aircraft turn at a very low altitude and collide with a 40-foot-tall power pole about 1/2 mile southeast of the airport. FAA inspectors from the San Diego FSDO responded to the accident site and examined the aircraft. In addition, a second and more detailed examination was conducted after recovery of the aircraft. According to the inspector's report, control system continuity was established from the cockpit controls to each control surface. The flap actuator was found in the up position. The carburetor was separated from the engine by impact damage; however, disassembly revealed no internal discrepancies. Compression was found in all four cylinders. Accessory gear and valve train continuity was established throughout the engine. The magnetos were secured to their respective mounting pads and timed to the engine. Both magnetos were removed and installed on a test bench where they were functioned satisfactorily. The surface weather observation taken at the airport at 1532 reported clear skies with a visibility of 30 miles. Utilizing a Safety Board computer program, the position of the sun at 1507 was calculated as 15.6 degrees above the horizon on a magnetic azimuth of 220 degrees from the accident site. Review of the pilot's logbook revealed that she had accumulated 75 total hours over two separate instructional periods; one in 1993, and the second in 1995. According to the logbook entries, the pilot had never flown into Imperial before. An autopsy was conducted by the Imperial County Coroner with specimens retained for toxicological analysis. The coroner reported that the pilot was 6 months pregnant and the case was therefore ruled a multiple fatality by the county. Results of the toxicological tests were negative for alcohol and all screened drug substances.

Probable Cause and Findings

the student pilot's misreading of the altimeter while in the traffic pattern, which put the aircraft in dangerous proximity to the ground and obstructions. A factor in the accident was the pilot's inability to see the power pole due to sun glare as the aircraft turned onto base from downwind.

 

Source: NTSB Aviation Accident Database

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